An infusion system for delivering a drug or other liquid into a patient typically includes a pump segment that couples to an infusion pump. The pump segment typically includes a tube segment that is operated upon by a pump mechanism for pumping fluid from a source of fluid, such as an intravenous (IV) bag toward the patient.
The tube segment may be made of a material, such as silicone, that is sufficiently pliable to be acted upon by the pump mechanism in order to create a repeatable volumetric displacement in the tube segment for causing fluid flow. Such a pliable material may also be at least partially permeable, which under some conditions, permits air to enter the tube segment, which is generally undesirable. In addition, dissolved air in the IV fluid and air introduced into the tube during priming may also be present. There is a need for devices and methods for dealing with air-in-line conditions for infusion pump systems.